Objective:Osteosarcoma is a highly aggressive primary malignant bone tumor commonly seen in children and adolescents,with a poor prognosis.Anchorage-dependent cell death(anoikis)has been proven to be indispensable in tumor metastasis,regulating the migration and adhesion of tumor cells at the primary site.However,as a type of programmed cell death,anoikis is rarely studied in osteosarcoma,especially in the tumor immune microenvironment.This study aims to clarify prognostic value of anoikis and tumor immune microenvironment-related gene in the treatment of osteosarcoma. Methods:Anoikis-related genes(ANRGs)were obtained from GeneCards.Clinical information and ANRGs expression profiles of osteosarcoma patients were sourced from the therapeutically applicable research to generate effective therapies and Gene Expression Omnibus(GEO)databases.ANRGs highly associated with tumor immune microenvironment were identified by the estimate package and the weighted gene coexpression network analysis(WGCNA)algorithm.Machine learning algorithms were performed to construct long-term survival predictive strategy,each sample was divided into high-risk and low-risk subgroups,which was further verified in the GEO cohort.Finally,based on single-cell RNA-seq from the GEO database,analysis was done on the function of signature genes in the osteosarcoma tumor microenvironment. Results:A total of 51 hub ANRGs closely associated with the tumor microenvironment were identified,from which 3 genes(MERTK,BNIP3,S100A8)were selected to construct the prognostic model.Significant differences in immune cell activation and immune-related signaling pathways were observed between the high-risk and low-risk groups based on tumor microenvironment analysis(all P<0.05).Additionally,characteristic genes within the osteosarcoma microenvironment were identified in regulation of intercellular crosstalk through the GAS6-MERTK signaling pathway. Conclusion:The prognostic model based on ANRGs and tumor microenvironment demonstrate good predictive power and provide more personalized treatment options for patients with osteosarcoma.

To examine the growth activity and osteogenic differentiation of bone mesenchymal stem cells (BMSCs) in rats with Type 2 diabetes mellitus (T2DM) as well as the expression level of Dickkopf-1 (DKK-1) in bone marrow, and to explore the relationship between the osteogenic activity of BMSCs and the expression of DKK-1.
 Methods: The BMSCs were isolated from T2DM rats and were cultured in vitro. The BMSCs were divided into a T2DM group and a control group. The proliferation of BMSCs was detected by cell counting kit-8 (CCK8). Apoptosis rate was detected by annexin V- fluorescein isothiocyanate (FITC)/propidium iodide (PI) double staining. In the osteogenic induction phase, the expression level of alkaline phosphatase (ALP) in BMSCs was detected by ALP staining and ALP activity assay kit. The osteogenic differentiation of BMSCs was analyzed by alizarin red staining and mineralized nodule quantification. In addition, the expression of Runx2 and DKK-1 in BMSCs was detected by qRT-PCR.
 Results: Compared with the control group, the proliferation of BMSCs was decreased and the apoptosis was increased in the T2DM group (both P<0.01). In the osteogenic induction process of BMSCs, the expression of ALP significantly decreased, the formation of calcium nodules reduced, and the expression of osteoblast transcription factor Runx2 was down-regulated in the T2DM group compared with those in the control group (all P<0.01). The levels of DKK-1 protein and mRNA were up-regulated in the T2DM group, which were higher than those in the control group (both P<0.01). The levels of DKK-1 protein and mRNA were related to the increase of Runx2 (both P<0.01).
 Conclusion: The growth activity of BMSCs and the potential of osteogenic differentiation are attenuated in the T2DM rats, which may be related to the increase of DKK-1 expression in BMSCs.
Animals ; Bone Marrow Cells ; Cell Differentiation ; Cells, Cultured ; Diabetes Mellitus, Experimental ; Diabetes Mellitus, Type 2 ; physiopathology ; Gene Expression Regulation ; Intercellular Signaling Peptides and Proteins ; genetics ; Mesenchymal Stem Cells ; Osteogenesis ; genetics ; Rats